The present invention is in the field of metal construction shapes and particularly those shapes used in the construction of metal windows and doors and frames therefor.
With the advent of metal construction used in curtain wall and other metal window and door enclosures, problems of heat conduction have arisen. The use of aluminum for the metal frames caused a greater transfer of heat between wall elements than had heretofore taken place in previous types of such construction. An insulation problem or the necessity for a thermal break construction element was thus essential. Various types of thermal breaks have been constructed, some of which have been satisfactory, but have been too costly. Other types have met with varying degrees of success.
Most thermal break constructions are currently formed by pouring in place an insulating material into the metal members or by mechanically joining the metal members and insulating member by deformation of the metal members. U.S. Pat. Nos. 3,204,324, 3,393,487, 3,624,885, 3,634,565 and 3,823,524 are illustrative of the former type of constructions. U.S. Pat. Nos. 3,093,217, 3,114,179, 3,420,026, and 3,411,995 are illustrative of the latter type of construction. U.S. Pat. Nos. 3,411,254, 3,289,377, 3,055,463 and 2,654,920 disclose additional prior art thermal break constructions.
Another means of mechanically joining metal members with an insulating member is disclosed in U.S. application Ser. No. 430,099, filed on Jan. 2, 1974, having a common ownership with the instant application. In this method, dimensional tolerances are essential to obtain a desired interference fit.
The present invention eliminates the necessity of expensive jigs which are required with pouring operations.
The instant invention permits some variances in dimensional tolerances providing a more economical construction.
Heat generated by metal deformation is also eliminated and metal marring and defacing is reduced.
Thermal break construction joints or lineal shapes of this invention have uniform strength and are relatively simple and easy to fabricate. The use of jig boxes and table space is also minimized.
It is a primary object of the present invention to provide a unitary thermo break connection or a thermally insulating break in metal construction shapes utilizing a rigid insulating member adapted to be mechanically received by the metal shapes which eliminates the need for exact dimensional tolerances.